nanos->millis

rate+latency

(rate+latency event)(rate+latency ev quantiles)

Returns a Metric which can be updated with latency measurements. When asked for events, returns a rate of total throughput, plus the given quantiles of latency metrics. Takes an optional base event which is used as the template. Input latencies are in nanoseconds (for storage as longs), emits latencies as doubles in milliseconds.